source: frontend/node_modules/es-iterator-helpers/test/Iterator.from.js

'use strict';

var defineProperties = require('define-properties');
var test = require('tape');
var callBind = require('call-bind');
var functionsHaveNames = require('functions-have-names')();
var hasProto = require('has-proto')();
var forEach = require('for-each');
var debug = require('object-inspect');
var v = require('es-value-fixtures');
var hasSymbols = require('has-symbols/shams')();
var hasPropertyDescriptors = require('has-property-descriptors')();
var mockProperty = require('mock-property');

var index = require('../Iterator.from');
var impl = require('../Iterator.from/implementation');

var isEnumerable = Object.prototype.propertyIsEnumerable;

var testIterator = require('./helpers/testIterator');

var $Iterator = require('../Iterator/implementation');
var iterProto = require('iterator.prototype');

var getCodePoints = function getCodePoints(str) {
        var chars = [];
        for (var i = 0; i < str.length; i++) {
                var c1 = str.charCodeAt(i);
                if (c1 >= 0xD800 && c1 < 0xDC00 && i + 1 < str.length) {
                        var c2 = str.charCodeAt(i + 1);
                        if (c2 >= 0xDC00 && c2 < 0xE000) {
                                chars.push(str.charAt(i) + str.charAt(i + 1));
                                i += 1;
                                continue; // eslint-disable-line no-continue, no-restricted-syntax
                        }
                }
                chars.push(str.charAt(i));
        }
        return chars;
};

module.exports = {
        tests: function (from, name, t) {
                t['throws'](
                        function () { return new from(); }, // eslint-disable-line new-cap
                        TypeError,
                        '`' + name + '` itself is not a constructor'
                );
                t['throws'](
                        function () { return new from({}); }, // eslint-disable-line new-cap
                        TypeError,
                        '`' + name + '` itself is not a constructor, with an argument'
                );

                forEach(v.primitives.concat(v.objects), function (nonIterator) {
                        if (typeof nonIterator !== 'string') {
                                t['throws'](
                                        function () { from(nonIterator).next(); },
                                        TypeError,
                                        debug(nonIterator) + ' is not an iterable Object'
                                );
                        }
                });

                t.test('actual iteration', { skip: !hasSymbols }, function (st) {
                        forEach(v.nonFunctions, function (nonFunction) {
                                var badIterable = {};
                                badIterable[Symbol.iterator] = nonFunction;
                                st['throws'](
                                        function () { from(badIterable).next(); },
                                        TypeError,
                                        debug(badIterable) + ' is not a function'
                                );
                        });

                        // st['throws'](
                        //      function () { return new from([]); }, // eslint-disable-line new-cap
                        //      RangeError,
                        //      '`' + name + '` iterator is not a constructor'
                        // );

                        forEach(v.strings, function (string) {
                                var stringIt = from(string);
                                testIterator(stringIt, getCodePoints(string), st, 'string iterator: ' + debug(string));
                        });

                        var arrayIt = from([1, 2, 3]);
                        st.equal(typeof arrayIt.next, 'function', 'has a `next` function');

                        st.test('__proto__ is Iterator.prototype', { skip: !hasProto }, function (s2t) {
                                var fakeIterator = {
                                        __proto__: iterProto,
                                        next: function () {}
                                };
                                s2t.ok(fakeIterator instanceof $Iterator, 'is an instanceof Iterator');
                                s2t.equal(typeof fakeIterator.next, 'function', 'fake iterator `.next` is a function');
                                s2t.equal(from(fakeIterator), fakeIterator, 'returns input when it is an instanceof Iterator');

                                s2t.end();
                        });

                        st.test('real iterators', { skip: !hasSymbols }, function (s2t) {
                                var iter = [][Symbol.iterator]();
                                // eslint-disable-next-line no-proto
                                var arrayIterHasIterProto = hasProto && iter.__proto__.__proto__ !== Object.prototype;
                                s2t.equal(
                                        from(iter),
                                        iter,
                                        'array iterator becomes itself',
                                        { skip: !arrayIterHasIterProto && 'node 0.12 - 3 do not have Iterator.prototype in the proto chains' }
                                );

                                s2t.end();
                        });

                        st.test('observability in a replaced String iterator', function (s2t) {
                                var originalStringIterator = String.prototype[Symbol.iterator];
                                var observedType;
                                s2t.teardown(mockProperty(String.prototype, Symbol.iterator, {
                                        get: function () {
                                                'use strict'; // eslint-disable-line strict, lines-around-directive

                                                observedType = typeof this;
                                                return originalStringIterator;
                                        }
                                }));

                                from('');
                                s2t.equal(observedType, 'string', 'string primitive -> primitive receiver in Symbol.iterator getter');
                                from(Object(''));
                                s2t.equal(observedType, 'object', 'boxed string -> boxed string in Symbol.iterator getter');

                                s2t.end();
                        });

                        st.test('262: get-next-method-only-once', { skip: !hasPropertyDescriptors }, function (s2t) {
                                var nextGets = 0;
                                var testIter = {
                                        next: function () {
                                                return { done: true, value: undefined };
                                        }
                                };
                                Object.defineProperty(testIter, 'next', {
                                        get: function () {
                                                nextGets += 1;
                                                return function () {
                                                        return { done: true, value: undefined };
                                                };
                                        }
                                });

                                var iter = from(testIter);
                                s2t.equal(nextGets, 1, 'next retrieved once on creation');
                                iter.next();
                                s2t.equal(nextGets, 1, 'next not retrieved again on next()');
                                iter.next();
                                s2t.equal(nextGets, 1, 'next still not retrieved again');

                                s2t.end();
                        });

                        st.test('262: get-next-method-throws', { skip: !hasPropertyDescriptors }, function (s2t) {
                                var testIter = {};
                                Object.defineProperty(testIter, 'next', {
                                        get: function () {
                                                throw new EvalError('next getter threw');
                                        }
                                });

                                s2t['throws'](
                                        function () { from(testIter); },
                                        EvalError,
                                        'throws when getting next throws'
                                );

                                s2t.end();
                        });

                        st.test('262: iterable-to-iterator-fallback', function (s2t) {
                                // When Symbol.iterator is null/undefined, treat object as iterator
                                var iteratorObj = {
                                        next: function () {
                                                return { done: true, value: undefined };
                                        }
                                };
                                iteratorObj[Symbol.iterator] = null;
                                var iter1 = from(iteratorObj);
                                s2t.equal(typeof iter1.next, 'function', 'iterator with null Symbol.iterator is treated as iterator');

                                var iteratorObj2 = {
                                        next: function () {
                                                return { done: true, value: undefined };
                                        }
                                };
                                iteratorObj2[Symbol.iterator] = undefined;
                                var iter2 = from(iteratorObj2);
                                s2t.equal(typeof iter2.next, 'function', 'iterator with undefined Symbol.iterator is treated as iterator');

                                s2t.end();
                        });

                        st.test('262: return-is-forwarded', function (s2t) {
                                var returnCalls = 0;
                                var testIter = {
                                        next: function () {
                                                return { done: false, value: 1 };
                                        },
                                        'return': function () {
                                                returnCalls += 1;
                                                return { done: true, value: undefined };
                                        }
                                };

                                var iter = from(testIter);
                                iter.next();
                                s2t.equal(returnCalls, 0, 'return not called before calling return()');
                                iter['return']();
                                s2t.equal(returnCalls, 1, 'return called once after return()');

                                s2t.end();
                        });

                        st.test('262: return-method-returns-iterator-result', function (s2t) {
                                // When base iterator has no return method, wrapper's return() returns { done: true, value: undefined }
                                var testIter = {
                                        next: function () {
                                                return { done: false, value: 1 };
                                        }
                                };

                                var iter = from(testIter);
                                iter.next();
                                var result = iter['return']();
                                s2t.equal(result.done, true, 'done is true');
                                s2t.equal(result.value, undefined, 'value is undefined');

                                s2t.end();
                        });

                        st.test('262: get-return-method-throws', { skip: !hasPropertyDescriptors }, function (s2t) {
                                var testIter = {
                                        next: function () {
                                                return { done: false, value: 1 };
                                        }
                                };
                                Object.defineProperty(testIter, 'return', {
                                        get: function () {
                                                throw new SyntaxError('return getter threw');
                                        }
                                });

                                var iter = from(testIter);
                                iter.next();
                                s2t['throws'](
                                        function () { iter['return'](); },
                                        SyntaxError,
                                        'throws when getting return throws'
                                );

                                s2t.end();
                        });

                        st.test('262: supports-iterator', function (s2t) {
                                // Non-iterable iterator objects (no Symbol.iterator, but has next)
                                var plainIterator = {
                                        next: function () {
                                                return { done: true, value: 42 };
                                        }
                                };

                                var iter = from(plainIterator);
                                s2t.equal(typeof iter.next, 'function', 'wrapped iterator has next method');
                                var result = iter.next();
                                s2t.equal(result.done, true, 'done is true');
                                s2t.equal(result.value, 42, 'value is passed through');

                                s2t.end();
                        });

                        st.test('262: supports-iterable', function (s2t) {
                                // Iterable objects work
                                var arr = [1, 2, 3];
                                testIterator(from(arr), [1, 2, 3], s2t, 'array iterable');

                                s2t.end();
                        });

                        st.end();
                });
        },
        index: function () {
                test('Iterator.from: index', function (t) {
                        module.exports.tests(index, 'Iterator.from', t);

                        t.end();
                });
        },
        implementation: function () {
                test('Iterator.from: implementation', function (t) {
                        module.exports.tests(impl, 'Iterator.from', t);

                        t.end();
                });
        },
        shimmed: function () {
                test('Iterator.from: shimmed', function (t) {
                        t.test('Function name', { skip: !functionsHaveNames }, function (st) {
                                st.equal(Iterator.from.name, 'from', 'Iterator.from has name "from"');
                                st.end();
                        });

                        t.test('enumerability', { skip: !defineProperties.supportsDescriptors }, function (et) {
                                et.equal(false, isEnumerable.call(Iterator, 'from'), 'Iterator.from is not enumerable');
                                et.end();
                        });

                        module.exports.tests(callBind(Iterator.from, Iterator), 'Iterator.from', t);

                        t.end();
                });
        }
};